<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <style>
    html {
        font-size: 100px;
    }
    
    div {
        width: 1rem;
        height: 1rem;
        background-color: #f40;
    }
    </style>
</head>

<body>
    <div></div>
</body>

</html>
